The Wilbur A. Sawyer Papers

As Director of Laboratories at the Rockefeller Foundation's International Health Division, Dr. Sawyer made inspection
tours of yellow fever and malaria control laboratories in South America and Africa. During May and June of 1930, he visited
RF operations in Brazil. Earlier that year, Raymond Shannon, a RF entomologist, had discovered that Anopheles gambiae mosquitoes
(apparently recently arrived from Africa) were breeding in Natal, Brazil. An outbreak of malaria had followed several weeks
later in Natal, causing concern among malaria-control staff.

The caption on the back of the photograph reads, "Natal, Brazil, June 9, 1930. Swamp where Anopheles gambiae was first
found in the Western Hemisphere, by Shannon."